Generally, in a vehicle, a weather strip for sealing a gap to prevent entrance of wind and rain or dust thereinto is provided, the gap being provided between a peripheral portion of a vehicle body opening portion (for example, a back door opening portion, a trunk opening portion, a front door opening portion, or a rear door opening portion) and a peripheral portion of a door body (for example, a back door, a trunk lid, a front door, or a rear door) that can open and close the vehicle body opening portion. The peripheral portion of the vehicle body opening portion is bordered with a combination of a side portion that extends substantially linearly and a corner portion that is bent to connect the side portion to another side portion. In many cases, the weather strip has a length corresponding to the peripheral portion of the vehicle body opening portion and is mounted along the opening edge. Therefore, it is necessary to attach the weather strip to the corner portion while bending the weather strip. However, in a case where the weather strip is bent to correspond to the corner portion, the hollow sealing portion of the weather strip unnaturally gets crushed, which may cause partial deterioration in sealing performance. In order to prevent the unnatural crushing of the hollow sealing portion, a design in which a wall thickness of a portion of the hollow sealing portion to be mounted on the corner portion is larger than a wall thickness of a portion of the hollow sealing portion to be mounted on the side portion may be adopted.
Patent Reference 1 (JP-A-S63-132022) discloses a weather strip for a vehicle in which the above-described design concept is embodied, and a method and a device for manufacturing the same. That is, in a weather strip according to an embodiment of Patent Reference 1, a sealing portion 13 of a weather strip A corresponding to a linear portion of a trunk lid has a true circular shape (FIG. 4), whereas a sealing portion 13a of a weather strip B corresponding to a projecting corner portion of the trunk lid is thick only in a side portion S (FIG. 5). In order to manufacture the weather strip in which the thickness of the sealing portion partially varies, in an extrusion device described in Patent Reference 1, a plurality of dies 2, 3, and 4 for a hollow sealing portion having different discharge port diameters are sequentially disposed in front of a die 1 for an attachment portion (trimmed portion) of a weather strip (FIG. 1). In addition, for example, in the die 2 for a sealing portion 13a, a sponge rubber material extrusion means 6 is connected to a connection structure 10 that is positioned at a position corresponding to the side portion S (FIG. 2). At an extrusion timing of the weather strip B corresponding to the projecting corner portion, the side portion S of the sealing portion 13a is made thick by increasing a screw rotation speed of the sponge rubber material extrusion means 6 to supply a large amount of rubber to the connection structure 10 of the die 2 (refer to Patent Reference 1, page 3, upper left column).